1. Field of the Invention
The invention relates to a power-saving technique and, more particularly, to an apparatus for auto-regulating an input power source of a driver.
2. Description of the Related Art
The issue of power-saving is becoming more and more important.
FIG. 1 is a block diagram showing a constant voltage source provided for a driver. As shown in FIG. 1, conventionally, the voltage of a power source input end VCC provided to a driver is a voltage source. The voltage source of the driver may be 5V or 12V. The central processing unit (CPU) on the motherboard is driven by directly providing a constant voltage source to the driver. However, the CPU is always in a light load state when a common user uses a computer, and the CPU is in a heavy load state only when it does intensive computing occasionally. Since the load varies with the usage of the motherboard, it is wasteful to provide 12V to the driver when the motherboard is in a light load state.
When the system is in a heavy load state, the voltage for driving the power switching components should be high. However, when the system is in a light load state, the voltage for driving the power switching components does not need a high voltage. As a result, the conventional manner of providing power by a constant voltage source is not flexible. The power source of the driver cannot be changed no matter whether the system is in a light load state or a heavy load state, and it results in an unnecessary loss of driving.